Embossing is part of Framework
Framework makes doing reedwork much more effective. Embossing is important to framework. Here, it helps us spot some reeds that are off-center at the base.
Harmonica customization is both an art and a science. By and large, we don't need lots of sophisticated equipment to get the job done. Sometimes, the task requires lots of precision like moving the base of a reed a small fraction of a millimeter to one side. We don't need a microscope. Your own eyes will do.
It would have been difficult to see and correct this problem had we not tightened up the tolerance of the slots.
This also addresses the point around how embossing should be done and whether to emboss relative to the reed or relative to the slot. I don't use a light box. I don't look through the slot when I emboss. I view from the top. I bring the sides in evenly.
I tried to make this graphic as realistic as possible. There's nothing like looking at a reedplate with your own eyes. Watch the video in full screen mode, pause and move back and forth to get a really good look at the relationship between the reeds and the